Also found in: Thesaurus, Medical, Legal, Encyclopedia.


adj. Archaic
Of, relating to, or induced by a mental disorder.

brain′sick′ly adv.
brain′sick′ness n.


(Psychiatry) relating to or caused by insanity; crazy; mad
ˈbrainˌsickly adv
ˈbrainˌsickness n



insane; crazy; mad.
[before 1000]
brain′sick`ly, adv.
brain′sick`ness, n.
ThesaurusAntonymsRelated WordsSynonymsLegend:
Adj.1.brainsick - affected with madness or insanitybrainsick - affected with madness or insanity; "a man who had gone mad"
insane - afflicted with or characteristic of mental derangement; "was declared insane"; "insane laughter"


Afflicted with or exhibiting irrationality and mental unsoundness:
Informal: bonkers, cracked, daffy, gaga, loony.
Chiefly British: crackers.
Idioms: around the bend, crazy as a loon, mad as a hatter, not all there, nutty as a fruitcake, off one's head, off one's rocker, of unsound mind, out of one's mind, sick in the head, stark raving mad.
References in periodicals archive ?
What begins as a story of hope for Jian Wan becomes a heart-wrenching search for identity in a violent and rapidly changing world, as he comes to envision China "in the form of an old hag so decrepit and brainsick that she would devour her children to sustain herself.
Henry V, V, 1, 20), "the bedlam brainsick duchess" (second part of Henry VI, III, 1, 51), "a bedlam and ambitious humour" (second part of Henry VI, V, 1, 132) (SL).